VOLCANO MONITORING USING LOW-COST MAGNETOMETERS: CASE STUDIES FROM ASKJA, ICELAND AND CORDON CAULLE, CHILE

Understanding subsurface magma dynamics is critical for monitoring and mitigating volcanic hazards, yet traditional geophysical methods are often costly and logistically challenging. This study evaluates the potential of low-cost magnetic monitoring systems (<$250 per unit) to detect volcanic unrest and constrain subsurface magmatic processes at two active volcanic systems: Askja volcano, Iceland and Cordon Caulle volcano, Chile. To determine the viability of this technique for volcanic hazard monitoring, its effectiveness is examined through highly simplified subsurface models that highlight its advantages and limitations. Magnetic monitoring relies on the principle that rocks that are heated above the Curie temperature lose their magnetic properties and become “magnetically transparent”. As magma moves through the subsurface, it alters the magnetic field at the surface, making magnetic monitoring a non-invasive and potentially low cost method for studying magmatic systems. Askja, located in Iceland's Northern Volcanic Zone, began inflating in 2021 after decades of subsidence. Fine resolution magnetic instruments were deployed around Askja in 2023, co-located with a lower cost alternative to monitor changes in magma storage and movement. Similarly, Cordon Caulle, In Chile's Southern Volcanic Zone, is a highly active system with a history of recent eruptions making it an ideal site to further assess and refine these methods. This study addresses three key questions: Can low cost magnetic monitoring systems reliably detect subsurface magma movement? What are the strengths and limitations of magnetic field data for identifying magma movement? And can this technique provide sufficient resolution for effective volcanic monitoring? Through analyzing results from these two volcanic systems and constructing simplified subsurface models, this research explores the feasibility of low-cost magnetic monitoring as a practical and scalable tool for studying active volcanoes.